docs: def _head_temp_file(self, temp_file, num_lines):
          """ Returns a list of the first num_lines lines from a temp file. """
          if not isinstance(num_lines, int):
              raise DagobahError('num_lines must be an integer')
          temp_file.seek(0)
          result, curr_line = [], 0
          for line in temp_file:
              curr_line += 1
              result.append(line.strip())
              if curr_line >= num_lines:
                  break
          return result